Vaccine skeptics, often called anti-vaxxers, are getting bolder with their message that vaccines are the product of a coverup by industry, government and media.
The Center for Nonproliferation Studies estimates North Korea has between 2,500 and 5,000 metric tons of chemical weapons.
There was a lack of information about a potentially catastrophic breach of a dam in the town of Isabella, as evacuations continued following Hurricane Maria.
An earthquake with a 6.1 magnitude shook southern Mexico on Saturday and was felt in the capital, where seismic alarms sounded, residents ran into the streets.
NBC News was granted a look at a first relief flight to Puerto Rico in which the charity Samaritan's Purse assembled 50,000 pounds of supplies.